1 error[E0499]: cannot borrow `my_struct.field` as mutable more than once at a time
2 --> $DIR/return_from_loop.rs:20:9
4 LL | let value = &mut my_struct.field;
5 | -------------------- first mutable borrow occurs here
7 LL | my_struct.field.push_str("Hello, world!");
8 | ^^^^^^^^^^^^^^^ second mutable borrow occurs here
11 | ----- first borrow later used here
13 error: aborting due to previous error
15 For more information about this error, try `rustc --explain E0499`.